Air brake cylinder release valve



May 30," 1944. L.. w. MCALPINE AIR BRAKE CYLINDER RELEASE VALVE 2 Sheets-Sheet l Filed Sept. 24, 1941 Attorney May 30, 1944- l.. w. MeALPlNE AIR BRAKE CYLINDER RELEASE VALVE Filed Sept. 24., l1941 2 SheebS-Sheet 2l lm'eufor Lawrence WMZAl/azne WN hh..

A ttarmg' Patented May 30, 1944 UNITED STATES rTENT OFFICE Lawrence W. McAlpine, Savannah, Ga., assigner of twenty per cent to Lawrence W. McAlpine, Jr., Savannah, Ga., arid twenty per cent to W11- liam E. Corr. Norfolk, Va.

Applicationseptember 24, 1941, serial No. 412,174

. e claims. ,(cl. 303-68)` My invention relates to` improvements in air lbrake systems asA utilized in railway cars, and particularly to a manually operable release valve for substantially .instantaneously bleeding the brake cylinders on a car without releasing the unused air pressure inthe auxiliary and emergency reservoirsy when two or moreI cars are to be separated, so that the time and-trouble presently involved in bleeding the entire braking equipment before making'up new trains and then recharging the entire system when the train is made up are reduced, and the primary object of my inventionis to yprovide a simple, practical and ecient arrangement of the character indicatedwhich'requires replacement only of the air released from the brake cylinderand brake pipe to recharge the brake system, and hence saves much operation and wear and tear on the air pumps.

Other important objects and advantages of my invention will be apparent from a reading 'of the following description taken in connection with the appended drawings, wherein for purposes of illustration I have shown a preferred embodiment of my invention.

In the drawings:v i

Figure 1 is a general schematic vview showing the location and operative arrangement of the invention in an air brake system.

Figure 2 is anenlarged left hand end elevational view of the release valve showing the latch thereof.

Figure 3` is' a longitudinal vertical sectional view taken through the release valve and show ing the same in operative position wherein the train is being handled by air. l

Figure 4 is an enlarged transverse Vertical sectional view taken throughiFigure 1 along the line 4 4 and looking toward the right in vthe direction of the arrow.

Referring to the drawings in detail, the nunmeral 5 generally designates the present release valve which preferably, although not, necessarily, consists of an elongated cylinder 6 having a por'-, tion of its right hand end closed by an end wall 'I which comprises the concentric reduced cylinder 8 which has communication as indicated by the numeral 9 only with thermain air line or brake pipe IIJ. From the end wall I to the left hand end of the cylinder 6 the cylinder 6 is substan tially uniform in diameter and at its left hand end has an internal ange II which acts as a partial closure for that end of the cylinder and as a support for the reduced internall cylinder vl2 which isarranged concentrically with respect to the cylinder 6. 1

The'side wall of the ycylinder 6 has the 1ongitudinallyspaced ports I3, I4, I5 and I6. The ports I3,` I5 and I6 are longitudinally aligned single openings, while the port I4 consists of a series 'of circumferentially spaced openings I'I whichV have' communication with an external manifold I8 encircling the cylinderfi. One leg I9 of'a Y-shaped pipe 2D has connection with the manifold I8, while the remaining leg of the Y-shaped pipe has connection as indicated by the numeral 2l wththe port I3.

The-portl I5 is connected by the pipe 22 directly with the brake cylinder 23, while the port I6 is open to the atmosphere. Y

Slidable withinV the cylinder 6 is a compound piston arrangement which is characterized by a single pistonv rod 24. Atits left hand end` the piston rod hasa reducedl shank 25 which is threaded into .a solid cylindrical follower or piston 2B whose inner. end is cupped as indicated by the numeral 21.

A portionofthe piston 26 .is slidable within the cylinder I2 and another portion thereof is exposed at the left hand` end of the cylinder 6 as indicated in Figure 3 of the drawings. 'I'hat portion of the piston 26 which isthus exposed is provided with a circumferential latching groove 28 into which isadapted .to fall a latch bar 29 which is pivotedas indicated by the numeral 3.0 on a suitable bracket y3| secured to the cylinder end, the free end of thelatch bar 29 being apertured or otherwise equipped as indicated by the numeral 32 for connection with an operating cable f or lever (notshown) mounted in a suitably con- Venient place` onA the cai-.for operation by the brakeman. A vertical expandingk Yspring 33 presses downwardly on the top of the latch bar 29 from a bracket-,34 mounted on the cylinder end as shown, so that whenever the piston 26 moves relative to thelatch bar Z9 so as to register the groove 28 with the latch bar, the latch bar will be pressed into place in the groove and thereby prevent further longitudinal `or axial movement ofthe piston 26 and the piston rod.24 which is connected thereto. The manual operation is employed only to withdraw the latch 29 from the groove 28 in the manner and for purposesexplained below.

On the piston rod 24 are two cup-shaped pistons 35 and 35, respectively; which in the present instance face toward the left hand end of the cylinder. The piston 35 is secured to the piston rod at a point such that in they operative position shown in Figure 3 of the drawings, the piston 35 abuts the open end of the cylinder I2 and at the same time is located between and cuts off communication between the ports I3 and Ill, with the latch bar 29 in place in the groove 28. In this position of the device the piston 33 is located between and cuts oif communication between the ports l5 and I6.

A small piston 31 is xed on the right hand end of the piston rod 24 and is located for action solely within the small cylinder 8. In the perative position of the device this 4small .piston is located adjacent the left hand end of the small cylinder 8.

Referring to Figure 1 of the ydrawingalit is seen that the release valve 5 is connected in the brake cylinder branch pipe 38 between the triple valve or A B valve 39 of a conventional air lbr'a'lte'sys'- tem and the brake cylinder 23, the triple-.or A1B valve 39 being connected by pipes 40 and 4I with the usual emergency and rauxiliary chambers of the reservoir 42. The main air lineor;brake;pipe 43 is connected .at 44 with the triple .valve or A B, as the case may be, and at I0 with-the right hand end of the release valve 5. The vvrelease valve 5 is thus connected fin the brakecylinder pipe by connecting one side of the pipe with vthe Y-shaped pipe 20 and the other side 4With lthe port l5 as at'22.

When it is desired to utilize the presentinvention to ybleed the brake system-preceding detachment of cars, the brake Vpipe pressure'havingbeen reduced in the usual manner, the manual means of a suitable character already 'alluded to is used to raise the latch 29 so as t0#alloW-the air vpressure accumulated in the chamber'4'5 at 'the left hand side of the Apiston 35, 'and inthe-space 'between ythe pistons 35 and 36 to Vpush the compound piston assembly toward the Vright -to a position in which the piston 35 blocks the ports 'M and 22 to hold the -unused Vair `in the Areservoir. In this position the piston 36 is to theright of the port i6 so as to connect the 'ports' f5 and I6, thereby allowing the compressed air within the brake cylinder 23 to escape through the pipe 22 into the cylinder Gand exhaust to'the'atmospherethrough the ,port I6.

When-the car is replaced in train Vand thebrake system is to be recharged, the pressure in the main 'air lin-e or brake pipe 43 is restored in the usual 'manner and this pressure is communicated to the 'small cylinder 8. The pressure against the small piston 31 then being greater than the pressure in the chamber 45, `the piston assembly moves toward the let'from the'ble'eding position `to the operating position shown in Figure 3 of the drawings, wherein the brakesystem is fully operative.

It vwill be observed that the usual time required to -bleed off 100 cars is about 50 minutes. The present device will bleed the brake cylinders as fast -as the length of the one hundred ears can be walked, or roughly in Vl5 minutes. 'This saving in terminal delay and in vlmoney for the services of a switch crew andsometimes those of a road crew which may be waiting :to make up a train, Vare very substantial- It will also be observed that the present practice of bleeding the Aair lon a car or train consists of draining all of the air from the 'brake system, necessitating recharging of the .entire brake system when placed in `train again, which recharging requires from seven to fifteen minutes, and there is considerable Wear and tear on the pumps and other mechanism involved.

In the iit) .air supply which was used in applying the brakes preceding the separation of the cars, since the .air in the reservoirs is not released but is retained when the brake cylinders are bled by the operation .of 'the `present invention.

Although I have shown and described herein la preferred embodiment of my invention, it is `to .be denitely understood that I do not wish "to vlimit the application of my invention thereto,

except as may be required by the scope of the subjoined claims.

Having thus described the invention, what is claimed as new is:

1. In an air '.bra'kesystem comprising a reservoir, an automatic valve, a main airline connected to said automatic valve, and a brake cylinder, a release valve arranged between said brake cylinder vand said automatic valve, said release valve 'being operable to closecommunication between said automatic valve and said brake cylinder :and hleedsaid brake cylinder to the atmosphere, said release valve comprising a. main cylinder having areduced external cylinder at one end in Icommunication with said kmain cylinder and an .internal .cylinder opening into said main cylinder at the opposite end of said rmain cylinder, said reduced .external vcylinder being connectedto said main arline, ableedport in the wall of .said main cylinderopening'to the atmosphere adjacent .said reducedexternal cylinder, a

brake cylinder port located longitudinally inwardly from said bleed port, first and second automatic valve ports longitudinally spaced adjacent 4the .opposite -end of the cylinder, a `compound `piston `comprising a piston -rod reciprocable insaidmain cylinder, saidpiston rod having a reduced pistonto work in said reduced external cylinder, a pair of main pistons spaced along `said piston rod and working .in said main cylinder, Aand a -solid .piston working through said internal cylinder,said piston rod and said main .pistons being arranged to normally occupy positions in which `communication between said rst and second ports is cut-oir within said .main cylinder and wherein communication `between said brake cylinder port and said bleed port is cut-off within said main cylinder and said brake cylinder is in effective condition, latch means on said main cylinder arranged .tolengage said solid piston to ,retain said normal positions of the main pistons, said latch means being releasable from said solid piston to permit theair pressure from one of said automatic valve `ports, to work against one of said main .pistons lto move said piston rod and lpistons to .positionsin .which said'bleed port and said brake cylinder port are in communication to bleed the brake cylinder.

2. lAn air brake system .according to claim l wherein said main piston rod has a further piston in said reduced externalcylinder with an air connection between said external cylinder and said main airline whereby entry of air pressure into `said reduced external cylinder operates to restore said ,main piston rod .and its pistons to their normal positions as the main airline .pressure is brought up to normal.

'3. In an air brake system comprising a reservoir, an'automatic valve, a main air line connected to said automatic valve, and a brake cylinder, a release valve arranged between said 'brake cylinder and said automatic valve, said release valve being operable to close communication between said automatic valve and said brake cylinder and bleed said brake cylinder to the atmosphere, said release valve comprising a main cylindel` having a reduced external cylinder at one end in cornmunication with said main cylinder and an internal cylinder opening into said main cylinder at the opposite end of said main cylinder, said reduced external cylinder being connected to said main air line, a bleed port in the wall of said main cylinder opening to the atmosphere adjacent said reduced external cylinder, a brake cylinder port located longitudinally inwardly from said bleed port, first and second automatic valve ports longitudinally spaced adjacent the opposite end of the cylinder, a compound piston comprising a piston rod reciprocable in said main cylinder, said piston rod having a reduced piston to Work in said. reduced external cylinder, a pair of main pistons spaced along said piston rod and working in. said main cylinder, and a solid piston working through said internal cylinder, said piston rod and said main pistons being arranged to normally occupy positions in which communication between said first and second ports is cut-oi` within said main cylinder and wherein communication between said brake cylinder port and said bleed port is cut-off within said main cylinder and said brake cylinder is in effective condition, latch means on said main cylinder arranged to engage said solid piston to retain said normal positions of the main pistons, said latch means being releasable from said solid piston to permit the air pressure from one of said automatic valve ports to work against one of said main pistons to move said piston rod and pistons to positions in which said bleed port and said brake cylinder port are in communication to bleed the brake cylinder, means for intercepting a portion of the air moving to the brake cylinder during a brake application whereby to cause the piston assembly to more to abnormal position when said latch means is manually operated to release the main piston to the effect of such intercepted pressure, and means for holding said pressure to resistl return ol said piston assembly to normal position until said automatic valve and allied parts have released said pressure to the atmosphere.

4. In an air brake system comprising a reservoir. an automatic valve, a main air line connected to said automatic valve, and a brake c vlinder, a release valve arranged between said brake cylinder and said automatic valve, said release valve being operable to close communication between said automatic valve and said brake 4cylinder and bleed said brake cylinder to the atmosphere, said release valve comprising a main cylinder having a reduced external cylinder at one end in communication with said main cylin der and an internal cylinder opening into said main cylinder at the opposite end of said main cylinder, said reduced external cylinder being connected to said main air line, a bleed port in the wall of said main cylinder opening to the atmosphere adjacent said reduced external cylinder, a brake cylinder port located longitudinally inwardly from said bleed port, rst and second automatic valve ports longitudinally spaced adjacent the opposite end of the cylinder, a compound piston comprising a piston rod reciprocable in said main cylinder, said piston rod having a reduced piston to work in said reduced external cylinder, a pair of main pistons spaced along said piston rod and working in said main cylinder, and a solid piston working through said internal cylinder, said piston rod and said main pistons being arranged to normally occupy positions in whi-ch communication between said rst and secend ports is cut-oir within said main cylinder and wherein communication between said brake cylinder port and said :bleed port is cut-oil within said main cylinder and said brake cylinder is in effective condition, latch means on said said main cylinder arranged to engage said solid piston to retain said normal positions of the main pistons, said latch means being releasable from said solid piston to permit the air pressure from one of said automatic valve ports to work against one of said main pistons to move said piston rod and pistons to positions in which said bleed port and said brake cylinder port are in communication to bleed the brake cylinder, and means whereby a minimum of air in the brake cylinder and valve device can cause movement of the piston assembly to abnormal positions although opposed by a full charged brake pipe or main air line.

5. In an airbrake system comprising a brake cylinder, a main air line, an air reservoir, and an automatic valve, such as an A B or triple valve effectively connecting said main air line to said brake cylinder and reservoir, said valve being operative upon a reduction of pressure in said main air line to conduct the reservoir air to said brake cylinder to apply the brake; release valve means connected between said automatic valve and said brake cylinder, said release valve normally occupying a first position eiecting communication between said automatic valve and said brake cylinder, said release valve being operable to a second position to cut-off communication between said brake cylinder and said automatic valve and reservoir and hold the air pressure in said reservoir while exhausting said brake cylinder to the atmosphere, said release valve has a piston rod and a manually releasable latch normally retainably engaging said piston rod to retain said valve in its normal position, said release valve comprising a cylinder having a port in communication with said automatic valve, with said piston rod working in said cylinder and having a piston in advance of said port, said piston rod further having a reverse piston working in a portion of said cylinder having communication only with said main airline, whereby in a released position of said latch the reservoir air pressure iS effective upon a reduction of main airline pressure to move said piston rod and piston from said first position to said second position, increase of the main airline pressure to normal operating pressure effectively moving said reverse piston to restore said pistons to said rst position.

6. In an airbrake system comprising a brake cylinder, a main air line, an air reservoir, and an automatic valve, such as an A B or triple valve effectively connecting said main air line to said brake cylinder and reservoir, said valve being operative upon a reduction of pressure in said main air line te conduct the reservoir air to said brake cylinder to apply the brake; release valve means connected between said automatic valve and said brake cylinder, said release valve normally occupying a first position effecting communication between said automatic valve and said brake cylinder, said release valve being operable to a sec- I main airline, whereby in a released position of said latch the reservoir air pressure is eiective upon a reduction of main airline pressure to move said piston rod and pistons from said first-position to said second position, increase of the main airline pressure to normal operating pressure eiectively moving said reverse piston to restore said pistons to said first position, said latch being arranged to automatically reengage said piston rod to retain the same as lsaid piston rod is restored to said first position.

LAWRENCE W. MCALPINE. 

